There are many compositions and processes used for enhancing the combustion of combustibles and/or preventing deposits and corrosion phenomena destined to be principally used in industrial firing installations and less in the home ones, because of their complexity and the relatively high cost.
One of the most used and applied processes for increasing the total energy produced by the combustion of liquid, gaseous and mostly fossil fuels, using burners, consists in the modification of the physical—chemical conditions of the combustion reaction. For this purpose, an activator liquid, more precisely a combination of chemical compounds with a surface inhibitor peroxidant, is introduced as an aerosol in the combustion air. In order to control the homolytic breaking of the chemical bonds of the combustible molecules, a steady contribution of free radicals—especially new oxygen free radicals—is acquired on purpose to eliminate the free-radical termination phase and assure a larger number of molecules participating in this reaction. Similarly, a composition capable of modifying the physical parameters of the combustible is also introduced into the combustion air, which allows all the molecular participants in this reaction to be effective. Simultaneously, the surface properties of a chemical combination introduced in the combustion air are also controlled through some surface agents. Lastly, for the reduction of boiler corrosion, corrosion inhibitors are also introduced into the combustion air.
The apparatus for carrying out the process includes an active carbon filter for air, vessels into which the said compositions are introduced, air dosage pumps of the piston, membrane or other type, as well as some slide-valves or intermediate regulates the flow adjustment. The air generated by the dosage pumps is bubbled into the compositions generating the aerosols, and the additive air flow so formed is regulated by using the intermediate slide-valves and mixed with the rest of the combustion air sent to the burners. In case the additivation air system is damaged, a safety device stops the combustible access to the burners.
Over time, both the process and the apparatus have undergone changes and improvements, but their functioning general principles are still the same.
Hence the known compositions include at least one compound capable of releasing active oxygen, the choice being preferably made between hydrogen peroxide and alkali or alkali-earth metals peroxides.
According to the known process, the peroxide used is previously introduced in a limited fraction of combustion air, reunited with a principal fraction of combustion air, and the both fractions are introduced in the combustion chamber, preferably at a burner nozzle level. To introduce the peroxide into the combustion air, the limited air fraction is passed through a liquid containing the peroxide. The other compositions are subjected to the same process. The improvements are related, in principal, to achieving the best compositions, and the precise parameters in which the process have to be developed, as well as improving the apparatus for obtaining a stabile and optimum flow. Another problem to be solved is achieving a simple, one alkaline metal based composition, a process and an installation which allow both the improvement of the used combustible combustion and the prevention of the appearance of deposits and corrosion phenomena and, in case the said deposits already exist, their elimination. Another purpose was its applicability both to industrial and home firing installations.
The Romanian patent To 113489, of the present applicant, successfully resolves this technical problem by starting from the use of the sulfuric acid permanently produced during the combustible combustion for the oxidation of the combustible stable particles (the unburned substances), by using a alkaline metal or salt-based composition for additivating the combustion air in industrial and home firing installations. The said composition consists, in a first preferred embodiment, in about 95% of 6% solution of potassium dichromate in de-mineralized water, 2-3% ammonia and 2-3% of nonadditive mineral oil. In another preferred embodiment the said composition consists in about 95% of 1% solution of potassium permanganate in de-mineralized water, 0.5-1% of ammonia and 4% of non-additive mineral oil, all the proportions being reported as the weight. The first embodiment is especially designed for liquid combustibles and the second preferred embodiment, much more active, for solid combustibles. The additivation process consists in diluting any of these compositions in distilled water, in quantity of 1/1 to 1/6 parts by weight, transforming it into an aerosol by using a fraction of a combustion air blast introduced into the furnace together with the rest of the combustion air, in proportion of 0.01-0.05% active solution to the total quantity of the air necessary for burning the liquid and gaseous combustible or 0.1-0.15% for solid combustible, all proportions being by weight. The dilution with distilled water of any composition is dependent on the temperature of the combustion air fraction blast namely the dilution is proportionally decreasing with the decreasing of the temperature.
The additive unit for treating the air necessary for the combination of combustibles, using the composition with the above mentioned characteristics, was quite simply. It included a single vessel provided with pneumatic stirrer. The vessel contained the chosen additive composition depending on the used combustible and a set of air ducts for transporting the additivated air to the burner. It also includes a compressor, which produces the necessary air for generating the aerosols and a regulating loop with the role of maintaining a constant proportion of active solution in the combustion air, depending on the total air quantity necessary for burning process. These technical solutions present some disadvantages:
the need to inject the additives into the combustibles in the case of certain combustibles and firing systems;
the need to increase the chemical stability of the said compositions, especially when great temperature variations occur in the environment.